Scientists cringe at the term “sea lice,” which are actually a parasite that attach themselves to fish. The stinging sensation and rash that swimmers experience is caused by thimble jellyfish larvae and is called “seabather's eruption.”

Swimmers can reduce their risk of being stung by not wearing T-shirts in the water, using sunscreen, practicing good hygiene and taking off wet swimsuits immediately after getting out of the ocean, the department reported.